I’d be honoured to defend rapist John Worboys

"That horrible man Worboys?" says barrister Alex McBride. "Of course I would have defended him. It was a plum case. I'd have been honoured to have got it."

We are talking the day after Lord Justice Moses angrily refused rapist taxi driver John Worboys an adjournment on his appeal against his convictions for rape and sexual assault. McBride, 40, is expanding on the arguments in his book, Defending the Guilty, that even the worst criminals deserve the best legal representation.

This pacily readable trawl through English criminal law is full of "war stories": the time McBride got a fraudster off by dressing her as a god-fearing granny; the violent assault case where he successfully discredited the victim's testimony; the glee he felt when police failed to introduce damning evidence against his car-thief client, who went free.

McBride won't be drawn on how he'd have defended Worboys at his original trial. He certainly wouldn't have tried to smarten him up for the jury. "It was such a serious case, and so well publicised, it wouldn't have made a difference if he'd walked to the dock in a peer's ermine," he says. "You'd look for anything to get your client off, but in a case like his there would be a lot of forensic evidence.

"But then look at the Jill Dando case. Poor Barry George was convicted on a very weak identification and very poor forensics. We [defence barristers] are there to see that evidence is presented fairly and that it means what it purports to mean."

In other words, to make sure that justice is governed by law, rather than by knee-jerk notions of revenge, or by the expedient needs of the police or the Crown Prosecution Service to secure convictions.

That said, doing his best for a client might mean advising him to plead guilty or not to appeal. "And it sounds like Worboys had no grounds for appeal. He basically wanted an open-ended time limit on the basis that his legal team had not asked at trial for proper forensic tests to be made. Which sounds like classic client baloney."

One of the most striking stories in his book relates how McBride persuaded a client to plead guilty to "putting his hand down a 14-year-old girl's pants and rummaging around", in order to secure a suspended sentence.

Wouldn't it have been better for the man, who had a previous conviction for assaulting minors, to be locked up? "I disagree entirely," says McBride. "He had a 16-year-old daughter who was halfway through her exams. He'd done a good job of bringing her up alone after his wife died. If he'd gone to prison, what would have happened to his daughter? By punishing someone you can also end up punishing others who don't deserve it."

McBride clearly believes that John Worboys deserves his sentence. He is glad Worboys' victims don't have to endure the possibility of an appeal. But the presumption of innocence until guilt is proven is the cornerstone of British law. "And I would rather see 10 guilty people go free than one innocent person go to jail," he says. "Miscarriages of justice happen more often than you hear about, and that is more offensive to the justice system, to civic society, and to my own moral compass than a guilty man walking free."

Defending the Guilty is published by Penguin on March 29, price £12.99.